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A030091
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Primes such that p and p^2 have same set of digits.
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2
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94583, 100469, 102953, 107251, 110923, 184903, 279863, 285101, 406951, 459521, 493621, 499423, 504821, 684581, 752681, 758141, 758941, 786431, 836291, 843701, 928637, 976513, 980261, 1008947, 1009859, 1024399, 1029647
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Conjecture: there exist some m and N for which a(n) = prime(m + n) for all n >= N. [Charles R Greathouse IV, Jun 29 2011]
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
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FORMULA
| Equals A000040 INTERSECTION A029793. - Jonathan Vos Post (jvospost3(AT)gmail.com), Jul 06 2008
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MATHEMATICA
| Select[Prime[Range[82000]], Union[IntegerDigits[#]]== Union[ IntegerDigits [#^2]]&] (* From Harvey P. Dale, Aug 12 2011 *)
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PROG
| (PARI) isA030091(n)=isprime(n)&&Set(Vec(Str(n)))==Set(Vec(Str(n^2))) \\ Charles R Greathouse IV, Jun 28 2011
(Haskell)
import Data.List (nub, sort)
import Data.Function (on)
a030091 n = a030091_list !! (n-1)
a030091_list =
filter (\x -> ((==) `on` (nub . sort . show)) x (x^2)) a000040_list
-- Reinhard Zumkeller, Aug 11 2011
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CROSSREFS
| Cf. A000040, A029793.
Sequence in context: A029754 A204473 A110845 * A128376 A206411 A128389
Adjacent sequences: A030088 A030089 A030090 * A030092 A030093 A030094
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KEYWORD
| nonn,base,nice
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AUTHOR
| Patrick De Geest (pdg(AT)worldofnumbers.com)
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